SEOUL, South Korea (CNN) -- North Korea has accused the South's navy of staging a serious provocation that could lead to a maritime conflict.

Pyongyang's warning came after South Korean patrol boats fired warning shots to repel North Korean navy vessels in the Yellow Sea on Monday.

The South Korean military said the warning shots were fired at the North Korean ships after they strayed into South Korean waters.

But North Korea's navy is blaming Seoul for the incident, with Pyongyang calling it an "unacceptable provocation".

On Tuesday, North Korean's official state news agency, KCNA, issued a statement quoting naval sources as saying that the North Korean boats were on a routine patrol when they were fired upon, according to South Korea's official Yonhap News Agency, which monitors KCNA.

"The South Korean armed forces deliberately committed this armed provocation which may give rise to another skirmish in the West Sea," the North's statement said.

The statement called on South Korea to punish those responsible and ensure such incidents don't happen again.

North Korea is one of the world's most authoritarian and secretive nations, with an economy in dire straits after decades of mismanagement.

Following World War II, the Korean peninsula was split, with the North coming under Communist domination and the South following the West.

North and South Korea have been divided since the 1950-53 Korean War and remain technically at war, never having signed a peace treaty.

When the Korean War ended in an armistice in 1953, the U.N. Command established the Northern Limit Line, a demarcation on the West Sea, to avoid clashes at sea.

But North Korea rejected it during the armistice negotiations, claiming a zone of 12 nautical miles instead of the three nautical miles set by the U.N.

As a result, the communist North does not observe the line, often sending fishing boats and naval ships into the zone.

Monday's incident follows a series of recent skirmishes between the divided countries.

One of the most serious occurred in June 2002, when four South Korean sailors were killed and 19 wounded after its navy clashed with North Korean boats off the peninsula's west coast.

A North Korean vessel also caught fire and is believed to have been destroyed, with an estimated 13 North Korean sailors killed.

North Korea blamed the South for starting that incident, saying its forces had acted in self-defense.